New Jersey Wildlife: Ruffed grouse

The ruffed grouse, an iconic species of forest ecosystems, is the only remaining grouse species to call New Jersey its home. New Jersey once was home to another grouse species, the heath hen, but that species became extinct in 1932.

The ruffed grouse is a "chicken-size" bird that is noted for its cryptic woodland camouflage and, when flushed, its explosive flight burst in a "whirr" of wings. In flight, ruffed grouse can accelerate to 25 miles per hour or more while dodging in and out of vegetation.

Across most of their range, ruffed grouse have two or more color phases (gray or reddish-brown). The name "ruffed" was derived from the shiny, black-brown colored neck feathers that are most prominent on the male. When the neck is in full display in defense of its territory, or attracting a mate, these feathers are extended into a "ruff."

Ruffed grouse are one of the most widely distributed upland game birds in North America, living now or recently in all of the Canadian Provinces and in 38 of the 49 states on the continent. In New Jersey, historic breeding records indicate their distribution to have been in 17 of the 21 counties, with most records concentrated in the north-northwestern part of the state, as well as the heart of the New Jersey Pinelands.

According to the state Division of Fish and Wildlife, New Jersey once had a thriving grouse population. In fact, NJDFW reports that during the 1940s and 1950s, up to 30,000 grouse were taken annually by hunters. Grouse populations are known to be cyclic, so although improved numbers were seen in the 1970s and '80s, the 1990s and 2000s have produced a period of sustained low numbers that unfortunately still continue today.

Ruffed grouse normally have a short life span and are susceptible to various diseases, parasites and harsh weather, as well as predation, but ruffed grouse have lived with these natural threats for thousands of years without any lasting effects on population. Hunting was studied as a possible cause of the decline, but research conducted by several states confirmed that hunting pressure has no effect on overall grouse numbers and survival.

Instead, the research confirmed that grouse populations are driven by the breeding success and subsequent numbers of young birds that provide continued growth of population. However, the studies also showed that 80% of young birds will not survive the first year. So why the high mortality rate in the first year? The overall consensus regarding what is the main cause of the decline of ruffed grouse is loss of suitable habitat.

While some grouse can be found in mature forests, the greatest population densities are found in younger-aged more vigorous forests that can fill their cover and food requirements. The diet of the ruffed grouse includes a diversity of buds of aspen, birch, cherry trees, as well as insects, seeds, berries, sumac, grapes, acorns and catkins. The ideal habitat for ruffed grouse comes between five and 25 years after land has had a disturbance where trees have died or were removed, allowing for new growth to occur.

In the early part the 20th century, farm abandonment and the succession of forests from silviculture practices and fires produced habitats that resulted in the greatest abundance of grouse in recent times.

But as forests mature under the suppression of fire or a shift in forest management to a more "hand-off" approach coupled with a lack of beneficial understory plants, their critical food and cover resources deteriorate in the shade of even-age overstocked forests.

Thus the very forest systems that once supported a thriving grouse population in New Jersey no longer possess the age class diversity and associated habitat qualities needed to support this majestic species in most of its historic range in the state.

Based on this information and population trends, New Jersey's State Wildlife Action Plan lists ruffed grouse as a "species of greatest conservation need."

This story is a weekly feature that runs with the cooperation of New Jersey Audubon. For more information about NJ Audubon or how to perform conservation efforts on your property, contact John Parke of NJ Audubon at john.parke@njaudubon.org or visit njaudubon.org